1. Field
This disclosure relates generally to semiconductors, and more specifically, to power usage in semiconductor detection circuits.
2. Related Art
Lower power consumption continues to have importance in data electronic systems, due, for example, to widespread use of electronics that are powered by batteries. Power conservation is not only particularly important for portable electronic devices, but is also important for automotive electronics which are also powered from a battery. To conserve power, many integrated circuits have a power saving feature commonly referred to as a sleep mode which is entered after a predetermined amount of circuit inactivity. In the sleep mode, the portions of the circuitry are powered down and thus are not fully functional. A minimum amount of circuit functionality however must remain. The circuitry which is necessary to be powered during a sleep mode of operation typically consumes a significant amount of power.
An example of an integrated circuit that has a sleep mode of operation is the MC33993 integrated circuit sold by Freescale Semiconductor. The MC33993 integrated circuit is designed to detect the closing and opening of up to twenty-two switch contacts. To detect the closing and opening of a switch contact, a comparator compares a predetermined constant reference voltage with a voltage of a capacitor coupled in parallel with the switch contact.